(B=4.156, C= .765, Head Height=.125) Nylon Locking Hole Plugs are available in a large selection of sizes from 3/16" to 4". Designed with multiple locks to positively snap in panel thicknesses ranging from 1/64" to 1/4". Locking Hole Plugs are used to close any round hole...like wiring outlets, chassis holes, access holes, and many more! Molded of heat stabilized Nylon (UL94V2). Suitable for critical or elevated tempurature applications. Available black, and can be supplied to match any color.